/Engine/Source/Editor/LevelEditor/Public/LevelViewportLayout.h
Maximize/immersive commands can be queued up at startup to be executed on the first tick. This is necessary, because these commands can't be executed until the viewport has a parent window, which might not be there upon viewport initialization
struct FMaximizeViewportCommand
bool
bAllowAnimation
bool
bImmersive
bool
bMaximize
bool
bToggle
FName
Viewport